pub const DEFAULT_UNKNOWN_TTL: Duration;Expand description
How long an unknown is reused, absent configuration.
Reasonable range: 10 to 300 seconds. This is the negative cache: a DID that does not resolve, a server that is down, an address this reader refuses. Holding it stops one unreachable repository from costing a fetch on every write that names it, and it is the shortest of the three because it is the one that recovers by itself.